Alloyed steel treatment with protein containing composition

ABSTRACT

Disclosed is an aqueous composition suitable for treating an alloyed steel surface, particularly stainless steel, in preparation for cold forming. In addition to protein, the composition may contain conventional components such as oxalate, activators, oxidizing agents and promoters, and catalysts. After treatment and application of a lubricant coating, excellent results may be obtained when the metal is cold formed.

United States Patent Okabe et al.

[4 Jan. 14, 1975 Filed: Aug. 21, 1973 Appl. No.: 390,261

Assignee:

Foreign Application Priority Data Aug. 26, 1972 Japan 47-84986 U.S. Cl 106/135, 106/147, 117/127,

148/614 A Int. Cl..... C08h 17/24, C08h 17/00, C23r 7/18 Field 01 Search 148/615 R, 6.14 A, 6.16; 106/135, 147; 260/118 References Cited UNITED STATES PATENTS s/1952 Henricks 148/614 A 2,740,774 4/1956 Rapkin 260/118 2,787,565 4/1957 de Pretto 148/615 3,175,964 3/1965 Watawabe 148/616 X 3,459,604 8/1969 Freeman 148/614 A OTHER PUBLICATIONS Chem. Abst., 68:79,648c.

Journal of Chromatography, V ol. 50, No. 3, pp. 413418,1970.

Chem. Abst., 58:1 1,033h, 1963.

Primary Examiner-Theodore Morris Attorney, Agent, or FirmArthur E. Kluegel 57 ABSTRACT Disclosed is an aqueous composition suitable for treating an alloyed steel surface, particularly stainless steel, in preparation for cold forming. In addition to protein, the composition may contain conventional components such as oxalate, activators, oxidizing agents and promoters, and catalysts. After treatment and application of a lubricant coating, excellent results may be obtained when the metal is cold formed.

8 Claims, No Drawings ALLOYED STEEL TREATMENT WITH PROTEIN CONTAINING COMPOSITION BACKGROUND OF THE INVENTION This invention relates to oxalate conversion baths for processing alloyed steel, particularly stainless steel for cold working.

It is an object of this invention to form very firmly adhesive coatings on alloyed steel chemically and to provide lubricating coating thereon suitable for cold working the alloyed steel.

Stainless steel materials have been conventionally treated to form lubricating oxalate conversion coatings for cold working such as pipe-drawing, wire-drawing and heading. Such coatings have been utilized in combination with a reactive sodium soap, solid soap, lubricant or the like. For stainless pipes, the oxalate conversion coatings have been conventionally combined with reactive sodium stearate to form a metal soap. In such a system, there are some shortcomings that since the oxalate conversion coatings are ferrous oxalate, it is easily convertible to the water-soluble ferric salt by oxidation and that the oxalate conversion coating is nonadhesive on the metal substrate, particularly on high nickel stainless steel. In such cases, crystals in the conversion coatings have been often stripped away from the substrate immediately before the die and the coatings have not met well the desired requirements during the simple cold-working operations.

SUMMARY OF THE INVENTION We have now found that lubricating coatings can be provided suitably on alloyed steel for cold working by forming very firmly adhesive conversion coatings on the alloyed steelby employing a bath in which one or more proteins are added in a total amount of at least 0.1 g/l to an oxalate conversion bath containing oxalic acid and/or an oxalate as the main ingredients and including also an activator, oxidizing agent and oxidizing promoter.

DETAILED DESCRIPTION The alloyed steel used in this invention include Type SUS-24, -27, -32, -41 and -62 specified in Japanese Industrial Standard and the like. It cannot be elucidated clearly why the addition of proteins achieves the aforementioned effects in this invention. In view of the fact that no significant effect could be observed for the experiments employing an amino acid itself such as glycine, L-alanine, L-valine, L-serine and the like, the advantageous effect must be derived from the stereometric formula of proteins including the peptide linkage.

Any source of protein may be used in this invention. Examples include gelatin, casein, egg yolk and the like. One or more proteins are added in a total amount of at least 0.1 'g/l, preferably greater than l g/l and economically less than l g/l.

In a total amount less than 0.1 g/l, the firmly adhesive oxalate conversion coating desired will not be formed on the alloyed steel. Above g/l, further improved results will not be obtained.

The bath composition other than the proteins cannot be restricted definitely within particular ranges. It depends on the characteristics required for cold working and drawing conditions of the alloyed steel selected. Any known oxalate conversion bath may be used, such as those disclosed in U.S. Pat. Nos. 3,459,604 and 3,632,452 incorporated herein by reference. Baths having the following ranges may be expected to give optimum results.

Oxalic acid as the main ingredient is suitably employed in an amount from about 5 to about I00 g/l. It may be replaced by an oxalate such as sodium oxalate or a mixture of oxalic acid and an oxalate.

As the activator, it is suitable to use one or more compounds selected from the group comprising hydrochloric acid, hydrofluoric acid, hydrofluorosilieic acid and alkali metal salts and ammonium salts thereof in a total amount from about 0.1 to about 20 g/l calculated as chloride or fluoride ions.

The oxidizing agents may include nitric acid, nitrous acid, chloric acid, and alkali metal salts thereof in an amount from about 0.1 to about 10 g/l.

The oxidizing promoters include thiosulfuric acid and sulfurous acid which liberate sulfur or oxygen, alkali metal salts thereof, sodium meta-nitrobenzene sulfonate and the like in an amount from about 0.] to about 20 g/l.

A catalyst may be added, if necessary, in an amount,

from about 0.1 to about 5 g/l and includes oxides, phosphates, sulfate, borates and the like of tin, manganese, chromium, iron, titanium, calcium, zinc and the like.

According to this invention, cleaned stainless steel defatted and pickled conventionally is soaked in an oxalate conversion bath having the composition as referred to hereinbefore at a temperature from about 60 to about 98C for 2 to 40 minutes. The coating formed according to this invention is so-c alled oxalate conversion containing ferrous oxalate as the main ingredient and is a lubricating coating of porous crystalline structure affixed firmly on the substratein a weight from about 2 to 30 g/m When the metal is drawn by applying a'lubricant, no

phenomenon such as stripping away, seizure or indentation of the coating in the cold working can be observed. Due to the firm oxalate conversion coating with sufficient adhesiveness and suitable thickness, cold worked articles of alloyed steel with a smooth surface can be obtained.

The following examples will illustrate the invention.

Examples 1 to 3 Composition of oxalate conversion bath:

Oxalic acid [(COOH) .2H O] 40. g/l Ammonium bifluoride lNH FHFl L5 g/l Sodium meta-nitrobenzene sulfonate [N0 .C H,.SO Na| 2 g/l Stannous oxide [SnO] 0.5 g/l The oxalate conversion bath was added with gelatin in an amount from 0.05 to l5 g/l to give the required baths. The baths were heated to a temperature from to C and stainless steel plates of Type SUS 27 50 X I50 X 1 mm were immersed in one of these baths for 20 minutes. The oxalate conversion coatings had a weight from 5 to 15 g/m Thereafter the specimens were affixed with Scotch tape by force after bending to -an angle of and the adhesiveness of coatings was measured by stripping off the tape suddenly. Another specimen was stretched by the use of an Amsler tensile testing machine until the specimen was broken and the adhesiveness of coating was measured at the most stretched condition of the specimen. The test results of the adhesiveness of coating are evaluated based on the following criterion:

3 The coating remains completely.

2 z The coating is stripped off to some extent.

l The coating remains to some extent.

The coating is stripped off completely. For comparison, an oxalate conversion coating was formed on another specimen of the same stainless steel plate by using the same oxalate conversion bath as specified except the absence of gelatine under the same conditions and the same bending and stretching tests were performed. These results are shown in Table l.

Example An oxalate conversion coating was formed on stainless steel pipe ofType SUS 32 having an outer'diametcr of 50 mm and a thickness of 8 mm with the same oxalating bath as disclosed in Example 2 under the same conditions. The pipe was drawn at a speed of 35 meters/min. to a sectional reduction of 35% in combina- It has been confirmed that the adhesiveness obtained from the baths according to this invention is improved markedly as compared to that obtained by using the bath containing no protein.

Examples 4 to 6 Oxalate conversion coatings were formed with the oxalate conversion baths added with casein in an amount from 0.05 to 5 g/ l in place of gelatine in the oxalating bath as disclosed in Examples 1 to 3 under the same conditions and bending and stretching tests were carried out, the results of which are shown in Table II TABLE II Test Amount of Bending Casein Test Stretching Test Example 4 0.05 g/l 2 2 2 2 3 3 Example 5 1 g/l 3 3 3 3 3 3 Example 6 5 gll 3 3 3 3 3 3 Control 0 g/l l 0 0 0 0 0 Examples 7 to 9 Oxalate conversion coatings were formed with oxalate conversion baths added with egg yolk in an amount from 0.05 to g/l in place of gelatine in the oxalating bath as disclosed in Examples 1 to 3 under the same conditions and bending and stretching tests were performed, the results of which being shown in Table Ill.

TABLE III Test Amount of Bending Egg Yolk Test Stretching Test Example 7 0.05 g/l 2 2 2 2 2 2 Example 8 5 g/l 3 3 3 3 3 3 Example 9 l5 g/l 3 3 3 3 3 3 Control 0 g/l l 0 0 O 0 0 tion with reactive sodium stearate. The outer and inner surfaces of the drawn pipe were very smooth and no stripping off of the coating or defects such as seizure 5 and indentation of the drawing operation due to the coating were observed. What is claimed is: 1. An aqueous composition suitable for treating an alloyed steel surface prior to cold forming comprising I from 5 to 100 g/l oxalate, at least 0.l g/l of a protein, and from 0.1 to g/l of an oxidizing agent selected from the nitrates, nitrites and chlorates.

2. The composition of claim 1 wherein said bath contains between 1 and 10 g/l of the protein.

3. An aqueous composition suitable for treating an alloyed steel surface prior to cold forming comprising from 5 to 100 g/l oxalate, at least 0.1 g/l of a protein, and from 0.1 to 5.0 g/l of a catalyst selected from the 40 oxides, phosphates, sulfates and borates of tin, manganese, chromium, iron, titanium, calcium and zinc.

4. The composition of claim 3 wherein said composition contains between 1 and 10 g/l of the protein.

5. The composition of claim 3 additionally comprising 0.1 to 20 g/l of an activator selected from hydrochloric, hydrofluoric and hydrofluosilicie acids and their salts.

6. The composition of claim 2 additionally comprising 0.1 to 20 g/l of an activator selected from hydrochloric, hydrofluoric and hydrofluosilicic acids and their salts.

7. A method of forming a firmly adherent coating on an alloyed steel surface suitable for subsequent lubrication and cold forming comprising contacting said surface with a composition comprising from 5 to l00 g/l oxalate and at least 0.1 g/l of a protein.

8. The method of claim 7 wherein said alloy is stainless steel and said composition contains between 1 and 10 g/l of said protein. 

1. AN AQUEOUS COMPOSITION SUITABLE FOR TREATING AN ALLOYED STEEL SURFACE PRIOR TO COLD FORMING COMPRISING FROM 5 TO 100 G/I OXALATE, AT LEAST 0.1 G/I OF A PROTEIN, AND FROM 0.1 TO 20 G/ G/I OF AN OXIDIZING AGENT SELECTED FROM THE NITRATED, NITRITES AN AND CHLORATES.
 2. The composition of claim 1 wherein said bath contains between 1 and 10 g/l of the protein.
 3. An aqueous composition suitable for treating an alloyed steEl surface prior to cold forming comprising from 5 to 100 g/l oxalate, at least 0.1 g/l of a protein, and from 0.1 to 5.0 g/l of a catalyst selected from the oxides, phosphates, sulfates and borates of tin, manganese, chromium, iron, titanium, calcium and zinc.
 4. The composition of claim 3 wherein said composition contains between 1 and 10 g/l of the protein.
 5. The composition of claim 3 additionally comprising 0.1 to 20 g/l of an activator selected from hydrochloric, hydrofluoric and hydrofluosilicic acids and their salts.
 6. The composition of claim 2 additionally comprising 0.1 to 20 g/l of an activator selected from hydrochloric, hydrofluoric and hydrofluosilicic acids and their salts.
 7. A method of forming a firmly adherent coating on an alloyed steel surface suitable for subsequent lubrication and cold forming comprising contacting said surface with a composition comprising from 5 to 100 g/l oxalate and at least 0.1 g/l of a protein.
 8. The method of claim 7 wherein said alloy is stainless steel and said composition contains between 1 and 10 g/l of said protein. 